The list measures net gains, after fees, of hedge fund managers since their respective fund's inception. We've included the top seven hedge fund managers below.

Collectively, these titans have made their investors net gains of $199.5 billion since they began their funds. Last year, they raked in $5.1 billion as a group. Two of the top fund managers had a losing year in 2015.

7. John Paulson (Paulson & Co.)

Highlights: In 2015, John Paulson fell from the No. 3 spot on the list to No. 7. He became famous for his 2007 bet against subprime housing; it made him and his investors billions. Since then his returns have been volatile, and his fund's assets have dropped from a peak of $38 billion in 2011 to about $15.6 billion. Just last month Paulson pledged his personal wealth as collateral for a line of credit for his fund from HSBC USA.

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6. Stephen Mandel (Lone Pine Capital)

Highlights: Lone Pine Capital is led by the billionaire Steve Mandel, who worked at legendary hedge fund Tiger Management early in his career. The fund is now part of a group of funds launched by Tiger alumni known as "Tiger Cubs."

Lone Pine's Cascade fund, its long-only fund, rose 1.4% in the fourth quarter to end 2015 down 1.2%. Meanwhile, Lone Pine's Cyprus fund rose 4.6% in the fourth quarter, ending the year up 8.7%, while its Kauri fund rose 4.4% in the quarter to end 2015 up 8.9%.

As of the end of 2015, the Cascade fund's 10 largest long-stock positions were Microsoft, Amazon, Tencent Holding, Facebook, Visa, Dollar Tree Stores, Williams Companies, FleetCor Technologies, JD.com, and Charter Communications. The fund trimmed some of its stake in embattled Canadian drug company Valeant Pharmaceuticals.

Highlights: Viking, which like Lone Pine is a "Tiger cub" hedge fund, had a strong 2015 overall, finishing up 8.3% for the year, according to the fund's fourth-quarter letter. The hedge fund bought more Valeant Pharmaceuticals stock in the fourth quarter, even after it dragged down the fund's performance and was its "biggest loser."

The fund's public-investments portfolio fell 6.7% in 2015, while the fund's private investments gained 2.4%, according to a separate investor update seen by Business Insider. The fund's public-investment returns were largely dragged down by Cheniere Energy, Micron Technology, Keryx Biopharmaceuticals, and Antero Resources.

2. George Soros (Quantum Endowment Fund)

Highlights: Quantum Endowment Fund, a family-office hedge fund, dropped from the No. 1 spot on last year's list to No. 2. Quantum, which had been led in recent years by Soros' protégé Scott Bessent, made $900,000,000 in net gains for 2015, the report said.

Soros has retired from the day-to-day operations of his fund, and is now focused on his foundations and philanthropy. At the World Economic forum in Davos this month, he sounded really bearish, saying that the next crisis will stem from China and the deflationary forces it's transmitting to the rest of the world.

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1. Ray Dalio (Bridgewater Pure Alpha)

Highlights: Dalio's Bridgewater Associates is the largest hedge fund in the world with approximately $160 billion under management. At the World Economic Forum in Davos this month, Dalio told Business Insider executive editor Jay Yarow that he's worried about growth in the global economy because there's no country acting as a "locomotive" right now.